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代码文件:
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, ComCtrls; type TForm1 = class(TForm) OpenDialog1: TOpenDialog; TrackBar1: TTrackBar; Timer1: TTimer; Button1: TButton; Button2: TButton; Button3: TButton; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure FormDestroy(Sender: TObject); procedure Timer1Timer(Sender: TObject); end; var Form1: TForm1; implementation {$R *.dfm} uses Bass; var hs: HSTREAM; {流句柄} {回调函数: MySync1; 尽管没有用到其中的任何参数, 但也要按指定的参数格式来写} procedure MySync1(handle: HSYNC; channel, data, user: DWORD); stdcall; begin Form1.Text := '开始播放了'; end; {回调函数: MySync2} {参数1: 是回调句柄, 它可有 BASS_ChannelSetSync 返回, 并可用 BASS_ChannelRemoveSync 删除} {参数2: 流句柄} {参数3: 不知道} {参数4: 是 BASS_ChannelSetSync 指定的用户数据} procedure MySync2(handle: HSYNC; channel, data, user: DWORD); stdcall; begin Form1.Text := '已过中点'; {假如播放到此(中间点)就从头反复, 可以这样:} //BASS_ChannelPlay(channel, True); end; {回调函数: MySync3; 尽管没有用到其中的任何参数, 但也必须按要求指定} procedure MySync3(handle: HSYNC; channel, data, user: DWORD); stdcall; begin Form1.Text := '播放完毕'; end; {初始化} procedure TForm1.FormCreate(Sender: TObject); begin TrackBar1.Height := 23; Timer1.Enabled := False; Timer1.Interval := 100; if HiWord(BASS_GetVersion) <> BASSVERSION then MessageBox(0, '"Bass.dll" 文件版本不合适! ', nil, MB_ICONERROR); if not BASS_Init(-1, 44100, 0, 0, nil) then ShowMessage('初始化错误'); end; {打开} procedure TForm1.Button1Click(Sender: TObject); var Mp3Path: AnsiString; Mp3Len: Cardinal; begin BASS_StreamFree(hs); Timer1.Enabled := False; OpenDialog1.Filter := 'Mp3 文件(*.mp3)|*.mp3|Wav 文件(*.wav)|*wav'; if OpenDialog1.Execute then Mp3Path := AnsiString(OpenDialog1.FileName); hs := BASS_StreamCreateFile(False, PAnsiChar(Mp3Path), 0, 0, 0); if hs < BASS_ERROR_ENDED then Text := '打开失败' else begin Text := string(Mp3Path); {先获取流的字节总长度, 下面有用} Mp3Len := BASS_ChannelGetLength(hs, BASS_POS_BYTE); TrackBar1.Max := Mp3Len; {开始播放是回调 MySync1} {参数1: 流句柄; 参数2: 参数类型; 参数3: 参数值; 参数4: 要回调函数指针; 参数5: 用户数据} BASS_ChannelSetSync(hs, BASS_SYNC_POS, 0, @MySync1, nil); {播放到中间时回调 MySync2} BASS_ChannelSetSync(hs, BASS_SYNC_POS, Mp3Len div 2, @MySync2, nil); {播放结束时回调 MySync3} BASS_ChannelSetSync(hs, BASS_SYNC_END, 0, @MySync3, nil); {当然也可以写做:} //BASS_ChannelSetSync(hs, BASS_SYNC_POS, Mp3Len, @MySync3, nil); {如果第二个参数同时指定 BASS_SYNC_ONETIME, 回调函数将只执行一次} BASS_ChannelSetSync(hs, BASS_SYNC_END or BASS_SYNC_ONETIME, 0, @MySync3, nil); end; end; {播放} procedure TForm1.Button2Click(Sender: TObject); begin BASS_ChannelPlay(hs, False); Timer1.Enabled := True; end; {暂停} procedure TForm1.Button3Click(Sender: TObject); begin BASS_ChannelPause(hs); Timer1.Enabled := False; end; procedure TForm1.FormDestroy(Sender: TObject); begin BASS_Free; end; procedure TForm1.Timer1Timer(Sender: TObject); begin if BASS_ChannelIsActive(hs) = BASS_ACTIVE_PLAYING then TrackBar1.Position := BASS_ChannelGetPosition(hs, BASS_POS_BYTE); end; end.窗体文件:
object Form1: TForm1 Left = 222 Top = 114 Caption = 'Form1' ClientHeight = 84 ClientWidth = 254 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False Position = poDesigned OnCreate = FormCreate OnDestroy = FormDestroy PixelsPerInch = 96 TextHeight = 13 object Button1: TButton Left = 8 Top = 18 Width = 75 Height = 25 Caption = #25171#24320 TabOrder = 0 OnClick = Button1Click end object Button2: TButton Left = 89 Top = 18 Width = 75 Height = 25 Caption = #25773#25918 TabOrder = 1 OnClick = Button2Click end object Button3: TButton Left = 170 Top = 18 Width = 75 Height = 25 Caption = #26242#20572 TabOrder = 2 OnClick = Button3Click end object TrackBar1: TTrackBar Left = 1 Top = 53 Width = 250 Height = 28 TabOrder = 3 end object OpenDialog1: TOpenDialog Left = 72 Top = 32 end object Timer1: TTimer OnTimer = Timer1Timer Left = 152 Top = 32 end end